Janus-shell liquid metal nanorobots for targeted bacterial eradication via microenvironment-triggered ion release

Metal ions are potent antibacterial agents, but suffer from uncontrolled ion release and toxicity. Here, we present Janus liquid metal nanorobots (J-LMNRs) with microenvironment-responsive ion release for precise antibacterial therapy. The J-LMNRs feature a gallium-based liquid metal (Ga-LM) core encapsulated in a Janus platinum (Pt)-polymer shell. The polymer shell modulates ion release thresholds from Ga-LM nanodroplet core, preventing premature activation in healthy tissues, while the asymmetric Pt in the shell amplifies subtle bacterial signals, such as acidic pH (~6.2) and trace hydrogen peroxide levels (~150 μM), into reactive oxide species (ROS) to trigger Ga 3+ ion release. This design enables autonomous chemotaxis towards infection sites and achieves 95% Staphylococcus aureus eradication within 12 h. By coupling signal amplification with adaptive chemical responsiveness, J-LMNRs minimize off-target toxicity and offer a paradigm shift for intelligent antibacterial systems.